Question

Your instructor (Katie) believes that the average time of taking this exam is equal to 140 minutes. A sample of 4 students was taken and the following exam times were obtained. Assume the distribution of the population is normally distributed. Sample: 150, 150, 180, 170 (Sample Std. Dev = 15) The correct set of hypothesis is: Hou < 140and H1 : > 140 a. Ho :u = 140 and Hiru # 140 Ob. Ho: u < 140 and Hı: u 140 ос. Hou 140 and Huu <140 O d.

Answer 1

THe correct set of Hypothesis is

$\\H_0:\mu=140 \\H_1:\mu\neq140$

We can use the t-test for testing. The test statistic is,

$t=\frac{\bar{X}-\mu}{\frac{s}{\sqrt{n}}}$

t Test for Hypothesis of the Mean
Data
Null Hypothesis                m=	140
Level of Significance	0.05
Sample Size	4
Sample Mean, X_bar	162.5
Sample Standard Deviation, s	15
Intermediate Calculations
Standard Error of the Mean	7.5000
Degrees of Freedom	3
t Test Statistic	3.0000
Two-Tail Test
Lower Critical Value	-3.1824
Upper Critical Value	3.1824
Do not reject the null hypothesis